Red blood on the legs may belong to the physiological phenomenon, but also may be caused by the adverse reaction of topical drugs, varicose veins of the lower extremities and other reasons. 1. Physiological phenomenon: for example, if the skin is naturally weak and relatively white, you can see the capillaries under the dermis, which will lead to the appearance of red blood on the legs. At this time, it is a normal physiological phenomenon, without special treatment. 2. Adverse reaction to topical drugs: If the legs suffer from inflammatory skin diseases such as psoriasis, eczema, etc., the long-term use of glucocorticoid ointment may cause thinning of the skin of the legs, capillary dilation and other conditions, which may also cause redness on the legs. 3. Varicose veins of the lower limbs: for example, long-term standing, sedentary, obesity and other factors can make the blood circulation impaired, which can lead to blood stagnation in the lower limbs, so that the internal pressure of the veins increases, and then varicose veins occur. This leads to the phenomenon of bulging and tortuous leg veins and the appearance of visible red blood. When the symptoms of red blood on the legs are all, you should avoid sitting and standing for a long time, and exercise appropriately. If the symptoms are serious, it is recommended to go to the hospital in a timely manner, to rule out other serious factors, and then actively carry out targeted treatment, to a certain extent, can alleviate the symptoms.